Method for producing semiconductor device

ABSTRACT

A method for producing a semiconductor device, including a semiconductor chip, for improving production efficiency and the flexibility of production design is provided. The method comprises: preparing a semiconductor chip having a first main surface on which an electroconductive member is formed; preparing a supporting structure in which, over a support configured to transmit radiation, a radiation curable pressure-sensitive adhesive layer and a first thermosetting resin layer are laminated in this order; arranging the semiconductor chips on the first thermosetting resin layer to face the first thermosetting resin layer to a second main surface of the semiconductor chips opposite to the first main surface; laminating a second thermosetting resin layer over the first thermosetting resin layer to cover the semiconductor chips; and curing the radiation curable pressure-sensitive adhesive layer by irradiating from the support side to peel the radiation curable pressure-sensitive adhesive layer from the first thermosetting resin layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for producing a semiconductordevice.

2. Description of the Related Art

In recent years, there has been spreading a tendency towards downsizingof semiconductor devices and miniaturization of interconnects thereofthat has been increasingly advancing. Thus, a greater number of I/O padsand vias are required to be arranged in a narrow semiconductor chipregion (a region of a semiconductor substrate that overlapssemiconductor chips when the chips are seen through in planar view).Simultaneously, the density of pins therein is also increasing.Furthermore, in a ball grid array (BGA) package, many terminals areformed in its semiconductor chip region, so that its region where otherelements are to be formed is restricted. Thus, a method of drawing out,on a semiconductor package substrate, wires from terminals in a regionoutside the chip region is adopted.

Under such a situation, if appropriate measures are taken case by casefor the downsizing of semiconductor devices and miniaturization ofinterconnects thereof, the production efficiency is reduced because ofthe extension of production lines, an increase in the complexity of theproduction process, and the like. Thus, such measures cannot fulfill arequirement of cost reduction.

To address this, in order to reduce costs for the production of asemiconductor package, a method of arranging plural chips, which havebeen made into individual pieces, on a support, and seating the chipsall together with a resin to form a package is suggested. For example,U.S. Pat. No. 7,202,107 discloses a method of arranging plural chips,which have been made into individual pieces, on a thermosensitiveadhesive formed on a support, forming a common carrier made of plasticmaterial to cover the chips and the thermosensitive adhesive, and thenpeeling the common carrier in which the chips are buried and thethermosensitive adhesive from each other by heating.

However, in the method for producing a semiconductor device according toU.S. Pat. No. 7,202,107, the thermosensitive adhesive is used to formthe common carrier. Thus, the adhesive imposes a limitation tohigh-temperature treatment. Furthermore, a cycle of heating andheat-dissipation is necessary. In light of these matters, there remainsroom for improvement from the viewpoint of the production efficiency ofsemiconductor devices, and the flexibility of the production designthereof.

SUMMARY OF THE INVENTION

Thus, an object of the present invention is to provide a method forproducing a semiconductor device that makes it possible to improve theproduction efficiency of the semiconductor devices, and the flexibilityof the production design thereof.

The inventors have made eager investigations and found out that theseproblems can be solved by use of a new supporting structure in whichsemiconductor chips are arranged, and a process using this structure. Asa result, the present invention has been accomplished.

That is, the present invention is a method for producing a semiconductordevice including a semiconductor chip, comprising:

preparing a semiconductor chip having a first main surface on which anelectroconductive member is formed;

preparing a supporting structure in which over a support configured totransmit radiation, a radiation curable pressure-sensitive adhesivelayer and a first thermosetting resin layer are laminated, in thisorder;

arranging the semiconductor chips on the first thermosetting resin layerto face the first thermosetting resin layer to a second main surface ofeach of the semiconductor chips that is opposite to the first mainsurface thereof;

laminating a second thermosetting resin layer over the firstthermosetting resin layer to cover the semiconductor chips; and

curing the radiation curable pressure-sensitive adhesive layer byirradiating from the support side to peel the radiation curablepressure-sensitive adhesive layer and the first thermosetting resinlayer from each other.

In this production method, by the use of the supporting structure inwhich over a support configured to transmit radiation, a radiationcurable pressure-sensitive adhesive layer and a first thermosettingresin layer are laminated, in this order, the semiconductor chipsarranged beforehand on the supporting structure are covered with thesecond thermosetting resin layer; and the subsequent curing of theradiation curable pressure-sensitive adhesive layer by the radiationmakes it possible to attain easy peeling of this radiation curablepressure-sensitive adhesive layer and the first thermosetting resinlayer from each other. Accordingly, no cycle of heating andheat-dissipation is required. Moreover, this method can efficiently copewith the production of semiconductor devices (packages) of varioustypes.

In this production method, it is preferred that the first thermosettingresin layer has a lowest melt viscosity of 5×10² Pa·s or more and 1×10⁴Pa·s or less at a temperature of 50 to 200° C. The first thermosettingresin layer has a lowest melt viscosity in the specified range, andtherefore, at the time of the laminating of the second thermosettingresin layer over the first thermosetting resin layer, the semiconductorchips arranged on the first thermosetting resin layer can be preventedfrom being shifted out of position (hereinafter, the shift may bereferred to as “chip shift”).

In this production method, it is preferred that the second thermosettingresin layer is a sheet-like thermosetting resin layer. When the secondthermosetting resin layer is in a sheet-like state, the semiconductorchips can be buried only by bonding the second thermosetting resin layeronto the first thermosetting resin layer in order to cover thesemiconductor chips. Thus, the production efficiency of thesemiconductor devices can be improved.

It is preferred that the second thermosetting resin layer comprises anepoxy resin, a phenolic resin, a filler, and an elastomer. Since thesecond thermosetting resin layer is formed by these components, thesemiconductor chips can be satisfactorily buried into the secondthermosetting resin layer when the second thermosetting resin layer isbonded over the first thermosetting resin layer.

This production method may further include exposing theelectroconductive members outward from a surface of the secondthermosetting resin layer after the laminating of the secondthermosetting resin layer and before the peeling of the radiationcurable pressure-sensitive adhesive layer. In this case, after theelectroconductive members are made exposed outward from the surface ofthe second thermosetting resin layer, a rewiring step may be performed.

Alternatively, the production method may further include, after thepeeling of the radiation curable pressure-sensitive adhesive layer,exposing the electroconductive members outward from the surface of thesecond thermosetting resin layer. In this case, after theelectroconductive members are made exposed outward from the surface ofthe second thermosetting resin layer, a rewiring step may be performed.

The production method may further include, after the peeling of theradiation curable pressure-sensitive adhesive layer, forming a rewireconnected to the exposed electroconductive members on the secondthermosetting resin layer in order that the rewire can be connected tothe substrate of the semiconductor devices to be obtained, or to someother component.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are sectional views that schematically illustrate anexample of a process for forming a supporting structure used in themethod for producing a semiconductor device of the invention; and

FIGS. 2A to 2G are schematic sectional views that respectivelyillustrate steps of the method for producing a semiconductor deviceaccording to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a method for producing a semiconductor deviceincluding a semiconductor chip, comprising:

preparing a semiconductor chip having a first main surface on which anelectroconductive member is formed;

preparing a supporting structure in which over a support configured totransmit radiation, a radiation curable pressure-sensitive adhesivelayer and a first thermosetting resin layer are laminated in this order;

arranging the semiconductor chips on the first thermosetting resin layerto face the first thermosetting resin layer to a second main surface ofeach of the semiconductor chips that is opposite to the first mainsurface thereof;

laminating a second thermosetting resin layer over the firstthermosetting resin layer to cover the semiconductor chips; and

curing the radiation curable pressure-sensitive adhesive layer byirradiating from the support side to peel the radiation curablepressure-sensitive adhesive layer and the first thermosetting resinlayer from each other.

Hereinafter, an embodiment of the invention will be described, referringto the attached drawings. FIGS. 1A and 1B are sectional views thatschematically illustrate an example of a process for forming asupporting structure used in the method for producing a semiconductordevice of the invention. FIGS. 2A to 2G are schematic sectional viewsthat respectively illustrate steps of the method for producing asemiconductor device according to the embodiment of the invention. Inthe description, the method for producing a semiconductor device will bediscussed first, and then the semiconductor devices yielded by thisproduction method will be generally described.

[Semiconductor Chip Preparing Step]

In a semiconductor chip preparing step, semiconductor chips 5 eachhaving a first main surface 5 a on which electroconductive members 6 areformed (see FIG. 2A) are prepared. The semiconductor chips 5 a may beformed by dicing a semiconductor wafer having a surface in whichcircuits are formed into individual pieces in a manner known in theprior art, or by some other method. The respective shapes of thesemiconductor chips 5 that are observed when the chips 5 are viewed inplan may be varied in accordance with target semiconductor devices. Theshapes may be square or rectangular shapes, the sides of each of theshapes having respective lengths selected independently from a range of1 to 15 mm.

The respective thicknesses of the semiconductor chips may be varied inaccordance with the respective sizes of the target semiconductordevices, and are, for example, from 10 to 725 μm, preferably from 30 to725 μm.

The electroconductive members 6, which are formed on the first mainsurfaces (circuit-forming surfaces) 5 a of the semiconductor chips 5,are not particularly limited, and examples thereof include bumps, pins,and leads. The material of the electroconductive members 6 is notparticularly limited, and examples thereof include solder materials(alloys) such as tin-lead based metal materials, tin-silver based metalmaterials, tin-silver-copper based metal materials, tin-zinc based metalmaterials, and tin-zinc-bismuth based metal materials; gold based metalmaterials; and copper based metal materials. The respective heights ofthe electroconductive members 6 may be decided in accordance with theusage thereof, and are generally from about 5 to 100 μm. Of course, onthe first main surfaces 5 a of the semiconductor chips 5, the respectiveheights of the individual electroconductive members 6 may be equal to ordifferent from each other.

[Supporting Structure Preparing Step]

In a supporting structure preparing step, a supporting structure 10 isprepared, in which over a support 4 configured to transmit radiation, aradiation curable pressure-sensitive adhesive layer 3 and a firstthermosetting resin layer 1 are laminated in this order (see FIGS. 1Aand 1B).

(Support)

The support 4 is a base for the strength of the supporting structure 10.The material of the support 4 is preferably a material that hasradiation-transmissibility, and that has a low stretch property forrestraining shifting of the chips, and some other purposes, and hasrigidity from the viewpoint of a handling property. Such a material ispreferably glass. As long as it satisfies the above mentionedproperties, examples thereof also include polyolefin such as low-densitypolyethylene, straight chain polyethylene, intermediate-densitypolyethylene, high-density polyethylene, very low-density polyethylene,random copolymer polypropylene, block copolymer polypropylene,homopolypropylene, polybutene, and polymethylpentene; anethylene-vinylacetate copolymer; an ionomer resin; anethylene(meth)acrylic acid copolymer; an ethylene(meth)acrylic acidester (random or alternating) copolymer; an ethylene-butene copolymer;an ethylene-hexene copolymer; polyurethane; polyester such aspolyethyleneterephthalate and polyethylenenaphthalate; polycarbonate;polyetheretherketone; polyimide; polyetherimide; polyamide; wholearomatic polyamides; polyphenylsulfide; aramid (paper); glass cloth; afluoropolymer resin; polyvinyl chloride; polyvinylidene chloride; acellulose resin; a silicone resin; metal (foil); and paper.

An example of a material of the support 4 includes a polymer such as across-linked body of the resins described above. The plastic films maybe used in a non-stretched state or may be used in a uniaxially orbiaxially stretched state as necessary. The same type or different typeof support made of resin can be appropriately selected and used as thesupport 4, and a support in which a plurality of materials are blendedcan be used depending on necessity.

A known surface treatment such as a chemical or physical treatment suchas a chromate treatment, ozone exposure, flame exposure, high voltageelectric exposure, and an ionized ultraviolet treatment, and a coatingtreatment by an undercoating agent (for example, a tacky substancedescribed later) can be performed on the surface of the support 4 inorder to improve adhesiveness, holding properties, etc. with theadjacent layer.

Further, a vapor-deposited layer of a conductive substance composed of ametal, an alloy, an oxide thereof, etc. and having a thickness of about30 to 500 angstrom can be provided on the support 4 in order to impartan antistatic function to the support 4. The support 4 may be a singlelayer or a multi layer of two or more types.

The thickness of the support 4 is not particularly limited, and may bedetermined appropriately. The thickness is generally from about 5 μm to2 mm, preferably from 100 μm to 1 mm when the handling property thereofis considered.

(Radiation Curable Pressure-Sensitive Adhesive Layer)

The adhesive strength of the radiation curable pressure-sensitiveadhesive layer 3 can be reduced easily by increasing the degree ofcrosslinking by irradiation (irradiation of an ultraviolet ray, electronray, X ray or the like).

For the radiation curable pressure-sensitive adhesive 3, thosesubstances having a radiation curable functional group such as acarbon-carbon double bond and having adherability can be used withoutparticular limitation. An example of the radiation curablepressure-sensitive adhesive is an addition-type radiation curablepressure-sensitive adhesive in which a radiation curable monomer oroligomer component is incorporated into a general pressure-sensitiveadhesive such as the acrylic pressure-sensitive adhesive or the rubberpressure-sensitive adhesive.

An example of the acrylic polymer is a polymer containing an acrylicester as a main monomer component. Specific examples of the acrylicester include an acryl polymer in which acrylate is used as a mainmonomer component. Examples of the acrylate include alkyl acrylate (forexample, a straight chain or branched chain alkyl ester having 1 to 30carbon atoms, and particularly 4 to 18 carbon atoms in the alkyl groupsuch as methyl ester, ethyl ester, propyl ester, isopropyl ester, butylester, isobutyl ester, sec-butyl ester, t-butyl ester, pentyl ester,isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexylester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecylester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester,octadecyl ester, and eicosyl ester) and cycloalkyl acrylate (forexample, cyclopentyl ester, cyclohexyl ester, etc.). These monomers maybe used alone or two or more types may be used in combination.

The acrylic polymer may optionally contain a unit corresponding to adifferent monomer component copolymerizable with the above-mentionedalkyl ester of (meth)acrylic acid or cycloalkyl ester thereof in orderto improve the cohesive force, heat resistance or some other property ofthe polymer. (Meth)acrylic acid refers to an acrylic acid and/or amethacrylic acid, and hereinafter, every occurrence of (meth) in thepresent application has a similar meaning with relation to the recitedcompound. Examples of such a monomer component includecarboxyl-containing monomers such as acrylic acid, methacrylic acid,carboxyethyl(meth)acrylate, carboxypentyl(meth)acrylate, itaconic acid,maleic acid, fumaric acid, and crotonic acid; acid anhydride monomerssuch as maleic anhydride, and itaconic anhydride; hydroxyl-containingmonomers such as 2-hydroxyethyl(meth)acrylate,2-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate,6-hydroxyhexyl(meth)acrylate, 8-hydroxyoctyl(meth)acrylate,10-hydroxydecyl(meth)acrylate, 12-hydroxylauryl(meth)acrylate, and(4-hydroxylmethylcyclohexyl)methyl(meth)acrylate; sulfonic acid groupcontaining monomers such as styrenesulfonic acid, allylsulfonic acid,2-(meth)acrylamide-2-methylpropanesulfonic acid,(meth)acrylamidepropanesulfonic acid, sulfopropyl(meth)acrylate, and(meth)acryloyloxynaphthalenesulfonic acid; phosphoric acid groupcontaining monomers such as 2-hydroxyethylacryloyl phosphate;acrylamide; and acrylonitrile. These copolymerizable monomer componentsmay be used alone or in combination of two or more thereof. The amountof the copolymerizable monomer(s) to be used is preferably 40% by weightor less of all the monomer components.

For crosslinking, the acrylic polymer can also contain multifunctionalmonomers if necessary as the copolymerizable monomer component. Suchmultifunctional monomers include hexane diol di(meth)acrylate,(poly)ethylene glycol di(meth)acrylate, (poly)propylene glycoldi(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritoldi(meth)acrylate, trimethylol propane tri(meth)acrylate, pentaerythritoltri(meth)acrylate, dipentaerythritol hexa(meth)acrylate,epoxy(meth)acrylate, polyester(meth)acrylate, urethane(meth)acrylate,etc. These multifunctional monomers can also be used as a mixture of oneor more thereof. From the viewpoint of adhesiveness etc., the use amountof the multifunctional monomer is preferably 30 wt % or less based onthe whole monomer components.

Preparation of the above acryl polymer can be performed by applying anappropriate method such as solution polymerization, emulsionpolymerization, bulk polymerization, and suspension polymerization to amixture of one or two or more kinds of component monomers, for example.Since the pressure-sensitive adhesive layer preferably has a compositionin which the content of low molecular weight materials is suppressedfrom the viewpoint of prevention of wafer contamination, and since thosein which an acryl polymer having a weight average molecular weight of300,000 or more, particularly 400,000 to 3,000,000 is a main componentare preferable from such a viewpoint, the pressure-sensitive adhesivecan be made to be an appropriate cross-linking type with an internalcross-linking method, an external cross-linking method, and the like.

An external crosslinking agent can be appropriately adopted in thepressure-sensitive adhesive to increase the weight average molecularweight of the acrylic polymer or the like that is the base polymer.Specific examples of an external crosslinking method include a method ofadding a so-called crosslinking agent such as a polyisocyanate compound,an epoxy compound, an aziridine compound, or a melamine crosslinkingagent and reacting to the product. When the external crosslinking agentis used, the used amount is appropriately determined by a balance withthe base polymer to be crosslinked and further by the application forthe pressure-sensitive adhesive. Generally, it is about 5 parts byweight or less, and preferably 0.1 to 5 parts by weight to 100 parts byweight of the base polymer. Further, various conventionally knownadditives, such as a tackifier and an antioxidant, may be used in thepressure-sensitive adhesive other than the above-described components asnecessary.

Examples of the radiation curable monomer component to be compoundedinclude an urethane oligomer, urethane(meth)acrylate, trimethylolpropanetri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate,pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritolhexa(meth)acrylate, and 1,4-butanediol di(meth)acrylate. Further, theradiation curable oligomer component includes various types of oligomerssuch as an urethane based, a polyether based, a polyester based, apolycarbonate based, and a polybutadiene based oligomer, and itsmolecular weight is appropriately in a range of about 100 to 30,000. Thecompounding amount of the radiation curable monomer component and theoligomer component can be appropriately determined to an amount in whichthe adhesive strength of the pressure-sensitive adhesive layer can bedecreased depending on the type of the pressure-sensitive adhesivelayer. Generally, it is for example 5 to 500 parts by weight, andpreferably about 40 to 150 parts by weight based on 100 parts by weightof the base polymer such as an acryl polymer constituting the pressuresensitive adhesive.

Further, besides the added type radiation curable pressure-sensitiveadhesive described above, the radiation curable pressure-sensitiveadhesive includes an internal radiation curable pressure-sensitiveadhesive using an acryl polymer having a radical reactive carbon-carbondouble bond in the polymer side chain, in the main chain, or at the endof the main chain as the base polymer. The internal radiation curablepressure-sensitive adhesives of an internally provided type arepreferable because they do not have to contain, and most do not contain,the oligomer component, or other component that is of a low molecularweight, and therefore they can form a pressure-sensitive adhesive layerhaving a stable layer structure without the oligomer component or otherlow molecular weight component migrating in the pressure sensitiveadhesive over time.

The above-mentioned base polymer, which has a carbon-carbon double bond,may be any polymer that has a carbon-carbon double bond and further isviscous. As such a base polymer, a polymer having an acrylic polymer asa basic skeleton is preferable. Examples of the basic skeleton of theacrylic polymer include the acrylic polymers exemplified above.

The method for introducing a carbon-carbon double bond into any one ofthe above-mentioned acrylic polymers is not particularly limited, andmay be selected from various methods. The introduction of thecarbon-carbon double bond into a side chain of the polymer is easier inmolecule design. The method is, for example, a method of copolymerizinga monomer having a functional group with an acrylic polymer, and thencausing the resultant product to condensation-react or addition-reactwith a compound having a functional group reactive with theabove-mentioned functional group and a carbon-carbon double bond whilekeeping the radiation curability of the carbon-carbon double bond.

Examples of the combination of these functional groups include acarboxylic acid group and an epoxy group; a carboxylic acid group and anaziridine group; and a hydroxyl group and an isocyanate group. Of thesecombinations, the combination of a hydroxyl group and an isocyanategroup is preferable from the viewpoint of the easiness of reactiontracing. If the above-mentioned acrylic polymer, which has acarbon-carbon double bond, can be produced by the combination of thesefunctional groups, each of the functional groups may be present on anyone of the acrylic polymer and the above-mentioned compound. It ispreferable for the above-mentioned preferable combination that theacrylic polymer has the hydroxyl group and the above-mentioned compoundhas the isocyanate group. Examples of the isocyanate compound in thiscase, which has a carbon-carbon double bond, include methacryloylisocyanate, 2-methacryloyloxyethyl isocyanate, andm-isopropenyl-α,α-dimethylbenzyl isocyanate. The used acrylic polymermay be an acrylic polymer copolymerized with any one of thehydroxyl-containing monomers exemplified above, or an ether compoundsuch as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether ordiethylene glycol monovinyl ether.

The intrinsic type radiation curable adhesive may be made only of theabove-mentioned base polymer (in particular, the acrylic polymer), whichhas a carbon-carbon double bond. However, the above-mentioned radiationcurable monomer component or oligomer component may be incorporated intothe base polymer to such an extent that properties of the adhesive arenot deteriorated. The amount of the radiation curable oligomer componentor the like is usually 30 parts by weight or less, preferably from 0 to10 parts by weight for 100 parts by weight of the base polymer.

The radiation curable pressure-sensitive adhesive preferably contains aphotopolymerization initiator in the case of curing it with anultraviolet ray or the like Examples of the photopolymerizationinitiator include α-ketol compounds such as4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone,α-hydroxy-α,α′-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone,and 1-hydroxycyclohexyl phenyl ketone; acetophenone compounds such asmethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone,2,2-diethoxyacetophenone, and2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin ethercompounds such as benzoin ethyl ether, benzoin isopropyl ether, andanisoin methyl ether; ketal compounds such as benzyl dimethyl ketal;aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonylchloride; optically active oxime compounds such as1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime; benzophenonecompounds such as benzophenone, benzoylbenzoic acid, and3,3′-dimethyl-4-methoxybenzophenone; thioxanthone compound such asthioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone,2,4-dimethylthioxanthone, isopropylthioxanthone,2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones;acylphosphonoxides; and acylphosphonates. The amount of thephotopolymerization initiator to be blended is, for example, from about0.05 to 20 parts by weight for 100 parts by weight of the acrylicpolymer or the like which constitutes the adhesive as a base polymer.

Further, examples of the radiation curable pressure-sensitive adhesivewhich is used in the formation of the pressure-sensitive adhesive layer2 include such adhesives as a rubber (pressure-sensitive adhesive or anacryl pressure-sensitive adhesive which contains anaddition-polymerizable compound having two or more unsaturated bonds, aphotopolymerizable compound such as alkoxysilane having an epoxy group,and a photopolymerization initiator such as a carbonyl compound, anorganic sulfur compound, a peroxide, an amine, and an onium saltcompound, which are disclosed in JP-A No. 60-196956. Examples of theabove addition-polymerizable compound having two or more unsaturatedbonds include polyvalent alcohol ester or oligoester of acryl acid ormethacrylic acid and an epoxy or a urethane compound.

The radiation curable pressure-sensitive adhesive layer 3 can contain acompound that is colored upon irradiation as necessary. By containingthe compound that is colored upon irradiation in the radiation curablepressure-sensitive adhesive layer 3, only a portion irradiated withradiation can be colored. Whether the radiation curablepressure-sensitive adhesive layer 3 is irradiated or not can thus bevisually determined right away.

The compound that colors upon irradiation is colorless or has a palecolor before the irradiation. However, it is colored upon irradiation. Apreferred specific example of the compound is a leuco dye. Common leucodyes such as triphenylmethane, fluoran, phenothiazine, auramine, andspiropyran dyes can be preferably used. Specific examples thereofinclude 3-[N-(p-tolylamino)]-7-anilinofluoran,3-[N-(p-tolyl)-N-methylamino]-7-anilinofluoran,3-[N-(p-tolyl)-N-ethylamino]-7-anilinofluoran,3-diethylamino-6-methyl-7-anilinofluoran, crystal violet lactone,4,4′,4″-trisdimethylaminotriphenylmethanol, and4,4′,4″-trisdimethylaminotriphenylmethane.

Examples of a developer that is preferably used with these leuco dyesinclude a prepolymer of a conventionally known phenolformalin resin, anaromatic carboxylic acid derivative, and an electron acceptor such asactivated white earth, and various color developers can be used incombination for changing the color tone.

The compound that colors upon irradiation may be included in theradiation curable pressure-sensitive adhesive after being dissolved inan organic solvent or the like, or may be included in thepressure-sensitive adhesive in the form of a fine powder. The ratio ofuse of this compound is 10% by weight or less, preferably 0.01 to 10% byweight, and more preferably 0.5 to 5% by weight in the radiation curablepressure-sensitive adhesive layer 3. When the ratio of the compoundexceeds 10% by weight, the curing of the radiation curablepressure-sensitive adhesive layer 3 becomes insufficient because theradiation onto the radiation curable pressure-sensitive adhesive layer 3is absorbed too much by this compound, and the adhesive strength may notreduce sufficiently. On the other hand, the ratio of the compound ispreferably 0.01% by weight or more to color the compound sufficiently.

The thickness of the radiation curable pressure-sensitive adhesive layer3 is not particularly limited, and is preferably from about 10 to 100μm, more preferably from 15 to 80 μm, and even more preferably from 20to 50 μm. If the thickness is larger than the upper limit of the range,a solvent for formation by application remains and the remaining solventis volatilized by heat in the process of producing the semiconductordevices such that the radiation curable pressure-sensitive adhesivelayer 3 may be unfavorably peeled off. If the thickness is smaller thanthe lower limit of the range, the pressure-sensitive adhesive layer 3does not deform sufficiently when the first thermosetting resin layer 1is peeled, so that the pressure-sensitive adhesive layer 3 is not easilypeeled.

(First Thermosetting Resin Layer)

The first thermosetting resin layer 1 of the present embodiment has afunction of holding the semiconductor chips 5 and protecting the rearsurfaces of the semiconductor chips 5 (second main surfaces 5 b thereof,which are opposite to the first main surfaces 5 a) when thesemiconductor devices are each mounted onto a substrate. Theconstituting material of the first thermosetting resin layer 1 may be acombination of a thermoplastic resin with a thermosetting resin, or maybe a thermoplastic resin alone or a thermosetting resin alone.

Examples of the thermoplastic resin include natural rubber, butylrubber, isoprene rubber, chloroprene rubber, ethylene/vinyl acetatecopolymer, ethylene/acrylic acid copolymer, ethylene/acrylic estercopolymer, polybutadiene resin, polycarbonate resin, thermoplasticpolyimide resin, polyamide resins such as 6-nylon and 6,6-nylon, phenoxyresin, acrylic resin, saturated polyester resins such as PET and PBT,polyamideimide resin, and fluoropolymer resin. These thermoplasticresins may be used alone or in combination of two or more thereof. Ofthese thermoplastic resins, acrylic resin is particularly preferablesince the resin contains ionic impurities in only a small amount and hasa high heat resistance so as to make it possible to ensure thereliability of the semiconductor chip.

The acrylic resin is not limited to any special kind, and may be, forexample, a polymer comprising, as a component or components, one or moreesters of acrylic acid or methacrylic acid having a linear or branchedalkyl group having 30 or less carbon atoms, in particular, 4 to 18carbon atoms. Examples of the alkyl group include methyl, ethyl, propyl,isopropyl, n-butyl, t-butyl, isobutyl, amyl, isoamyl, hexyl, heptyl,cyclohexyl, 2-ethylhexyl, octyl, isoortyl, nonyl, isononyl, decyl,isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, octadecyl, andeicosyl groups.

A different monomer which constitutes the above-mentioned polymer is notlimited to any especial kind, and examples thereof includecarboxyl-containing monomers such as acrylic acid, methacrylic acid,carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleicacid, fumaric acid, and crotonic acid; acid anhydride monomers such asmaleic anhydride and itaconic anhydride; hydroxyl-containing monomerssuch as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,4-hydroxybutyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate,8-hydroxyoctyl(meth)acrylate, 10-hydroxydecyl(meth)acrylate,12-hydroxylauryl(meth)acrylate, and (4-hydroxymethylcyclohexyl)methylacrylate; monomers which contain a sulfonic acid group, such asstyrenesulfonic acid, allylsulfonic acid,2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl(meth)acrylate, and(meth)acryloyloxynaphthalenesulfonic acid; and monomers which contain aphosphoric acid group, such as 2-hydroxyethylacryloyl phosphate.

Examples of the above-mentioned thermosetting resin include phenolresin, amino resin, unsaturated polyester resin, epoxy resin,polyurethane resin, silicone resin, and thermosetting polyimide resin.These resins may be used alone or in combination of two or more thereof.Particularly preferable is epoxy resin, which contains ionic impuritieswhich corrode semiconductor chips only a small amount. As the curingagent of the epoxy resin, phenol resin is preferable.

The epoxy resin may be any epoxy resin that is ordinarily used as anadhesive composition. Examples thereof include bifunctional orpolyfunctional epoxy resins such as bisphenol A type, bisphenol F type,bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol Atype, bisphenol AF type, biphenyl type, naphthalene type, fluorene type,phenol Novolak type, orthocresol Novolak type, tris-hydroxyphenylmethanetype, and tetraphenylolethane type epoxy resins; hydantoin type epoxyresins; tris-glycicylisocyanurate type epoxy resins; and glycidylaminetype epoxy resins. These may be used alone or in combination of two ormore thereof. Among these epoxy resins, particularly preferable areNovolak type epoxy resin, biphenyl type epoxy resin,tris-hydroxyphenylmethane type epoxy resin, and tetraphenylolethane typeepoxy resin, since these epoxy resins are rich in reactivity with phenolresin as an agent for curing the epoxy resin and are superior in heatresistance and so on.

The phenol resin is a resin acting as a curing agent for the epoxyresin. Examples thereof include Novolak type phenol resins such asphenol Novolak resin, phenol aralkyl resin, cresol Novolak resin,tert-butylphenol Novolak resin and nonylphenol Novolak resin; resol typephenol resins; and polyoxystyrenes such as poly(p-oxystyrene). These maybe used alone or in combination of two or more thereof. Among thesephenol resins, phenol Novolak resin and phenol aralkyl resin areparticularly preferable, since the connection reliability of thesemiconductor device can be improved.

In regards to the blend ratio between the epoxy resin and the phenolresin, for example, the phenol resin is blended with the epoxy resin insuch a manner that the hydroxyl groups in the phenol resin is preferablyfrom 0.5 to 2.0 equivalents, more preferably from 0.8 to 1.2 equivalentsper equivalent of the epoxy groups in the epoxy resin component. If theblend ratio between the two is out of this range, the curing reactiontherebetween does not advance sufficiently so that properties of thecured epoxy resin easily deteriorate.

In the present invention, a thermosetting resin comprising the epoxyresin, the phenol resin, and an acrylic resin is particularlypreferable. Since these resins contain only a small amount of ionicimpurities and have high heat resistance, the reliability of thesemiconductor chip can be ensured. In regards to the blend ratio in thiscase, the amount of the mixture of the epoxy resin and the phenol resinis from 10 to 200 parts by weight for 100 parts by weight of the acrylicresin component.

The thermal curing accelerator catalyst for the epoxy resin and thephenol resin is not especially limited, and it is appropriately selectedfrom known thermal curing accelerator catalysts. The thermal curingaccelerator catalyst can be used alone or two types or more of them canbe used in combination. Examples of the thermal curing acceleratorcatalyst that can be used include an amine curing accelerator, aphosphorus curing accelerator, an imidazole curing accelerator, a boroncuring accelerator, and a phosphorus-boron curing accelerator.

In order to crosslink the constituents of the first thermosetting resinlayer of the present invention to some extent in advance, it ispreferable to add, as a crosslinking agent, a polyfunctional compoundwhich reacts with functional groups of molecular chain terminals of theabove-mentioned polymer to the materials used when the sheet 12 isproduced. In this way, the adhesive property of the sheet at hightemperatures is improved so as to improve the heat resistance.

The crosslinking agent may be one known in the prior art. Particularlypreferable are polyisocyanate compounds, such as tolylene diisocyanate,diphenylmethane diisocyanate, p-phenylene diisocyanate, 1,5-naphthalenediisocyanate, and adducts of polyhydric alcohol and diisocyanate. Theamount of the crosslinking agent to be added is preferably set to 0.05to 7 parts by weight for 100 parts by weight of the above-mentionedpolymer. If the amount of the crosslinking agent to be added is morethan 7 parts by weight, the adhesive force is unfavorably lowered. Onthe other hand, if the adding amount is less than 0.05 parts by weight,the cohesive force is unfavorably insufficient. A differentpolyfunctional compound, such as an epoxy resin, together with thepolyisocyanate compound may be incorporated if necessary.

Further, an inorganic filter can be appropriately incorporated into thefirst thermosetting resin layer 1. By incorporation of the inorganicfiller, electric conductivity may be imparted, thermal conductivity maybe improved, and the storage modulus may be adjusted.

Examples of the inorganic fillers include various inorganic powders madeof the following: a ceramic such as silica, clay, plaster, calciumcarbonate, barium sulfate, aluminum oxide, beryllium oxide, siliconcarbide or silicon nitride; a metal such as aluminum, copper, silver,gold, nickel, chromium, lead, tin, zinc, palladium or solder, or analloy thereof; and carbon. These may be used alone or in combination oftwo or more thereof. Among these, silica, in particular fused silica, ispreferably used.

The average particle size of the inorganic filler is preferably within arange of 0.1 to 5 μm, and more preferably within a range of 0.2 to 3 μm.When the average particle size of the inorganic filler is less than 0.1μm, it becomes difficult to make Ra of the first thermosetting resinlayer be 0.15 μm or more. On the other hand, when the average particlesize exceeds 5 μm, it becomes difficult to make Ra less than 1 μm. Inthe present invention, two or more types of inorganic filters having adifferent average particle size may be used in combination. The value ofthe average particle size is obtained using a luminous intensity typeparticle size distribution meter (manufactured by HORIBA, Ltd., devicename: LA-910).

The blend amount of the inorganic filler is preferably set to 20 to 80parts by weight to 100 parts weight of the organic resin component. Itis especially preferably 20 to 70 parts by weight. If the blend amountof the inorganic filler is less than 20 parts by weight, the contactarea between the radiation curable pressure-sensitive adhesive layer 3and the first thermosetting resin layer 1 becomes large so that the twomay not be easily peeled from each other. If the blend amount is morethan 80 parts by weight, the contact area conversely becomes too smallso that the two may be unintentionally peeled from each other in theprocess of producing the semiconductor devices.

If necessary, other additives besides the inorganic filler may beincorporated into the first thermosetting resin layer 1 of the presentinvention. Examples thereof include a flame retardant, a silane couplingagent, and an ion trapping agent. Examples of the flame retardantinclude antimony trioxide, antimony pentaoxide, and brominated epoxyresin. These may be used alone or in combination of two or more thereof.Examples of the silane coupling agent includeβ-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane, andγ-glycidoxypropylmethyldiethoxysilane. These may be used alone or incombination of two or more thereof. Examples of the ion trapping agentinclude hydrotalcite and bismuth hydroxide. These may be used alone orin combination of two or more thereof.

The first thermosetting resin layer 1 preferably has a lowest meltviscosity in the range of 5×10² Pa·s or more and 1×10⁴ Pa·s or less at atemperature of 50 to 200° C. In a case where the first thermosettingresin layer 1 has a lowest melt viscosity in this range, at the time ofthe laminating of the second thermosetting resin layer 2 on the firstthermosetting resin layer 1, the semiconductor chips 5 arranged on thefirst thermosetting resin layer 1 can be prevented from being shiftedout of position. Further, in a case where the first thermosetting resinlayer 1 has the above-described lowest melt viscosity, the radiationcurable pressure-sensitive adhesive layer 3 and the first thermosettingresin layer 1 can easily be peeled from each other at the interfacebetween the radiation curable pressure-sensitive adhesive layer 3 andthe first thermosetting resin layer 1 after the formation of the secondthermosetting resin layer 2.

The thickness of the first thermosetting resin layer 1 (the thicknessis, when the first thermosetting resin layer is composed of plurallayers, the total thickness) is not particularly limited. The thicknessis preferably in the range of 5 μm or more and 250 μm or less inconsideration of the performance of holding the semiconductor chips 5,and a matter that the semiconductor chips 5 should be certainlyprotected after the first thermosetting resin layer 1 is cured.

The first thermosetting resin layer is preferably colored. This makes itpossible to cause the semiconductor devices to exhibit excellent markingproperties and external appearance. Thus, the semiconductor chips havingvalue-added external appearances can be obtained. The colored firstthermosetting resin layer has excellent marking performance as describedherein; thus, when a marking method that may be of various types, suchas a printing or laser marking method, is applied, through the aid ofthe colored first thermosetting resin layer, to non-circuit surfaces(that is, the second main surfaces 5 b) of the semiconductor chips orthe semiconductor devices wherein the semiconductor chips are used, thesemiconductor devices can be marked so that various pieces ofinformation, such as character or graphic information pieces, can begiven to the devices. In particular, by controlling the color of thecolored layer, information pieces given by the marking (such ascharacter or graphic information pieces) can be observed with excellentvisibility. Further, when the first thermosetting resin layer iscolored, the radiation curable pressure-sensitive adhesive layer and thefirst thermosetting resin layer can easily be distinguished from eachother, improving in workability and other properties. Furthermore, it ispossible to color different product, i.e., semiconductor devices, indifferent colors. When the first thermosetting resin layer is rendered acolored layer, which is not transparent and colorless, the color of thecolored layer is not particularly limited. Preferred examples thereofinclude deep colors such as black, blue, and red. A particularlypreferred example thereof is black.

In the present embodiment, deep colors basically mean colors eachpermitting L* specified in the L*a*b* color coordinate system to be 60or less (0 to 60), preferably 50 or less (0 to 50), more preferably 40or less (0 to 40).

Black means any black based color permitting L* specified in the L*a*b*color coordinate system to be 35 or less (0 to 35), preferably 30 orless (0 to 30), more preferably 25 or less (0 to 25). In regards to theblack, a* and b* specified in the L*a*b* color coordinate system mayeach be appropriately selected in accordance with the value of L*. Forexample, the value of each of a* and b* is preferably from −10 to 10,more preferably from −5 to 5, even more preferably from −3 to 3 (inparticular preferably 0, or about 0).

In the present embodiment, L*, a* and b* specified in the L*a*b* colorcoordinate system may be analyzed by making a measurement using acolor-difference meter (trade name: “CR-200”, manufactured by MinoltaCo., Ltd.). The L*a*b* color coordinate system is a color spacerecommended by the International Commission on Illumination (CIE) in1976, and denotes a color space named the CIE 1976 (L*a*b*) colorcoordinate system. The L*a*b* color coordinate system is also prescribedin JIS Z 8729 according to the Japanese Industrial Standard.

When the first thermosetting resin layer is colored, a color material(coloring agent) may be used in accordance with a target color. Suchcolor materials are preferably black based color materials, blue basedcolor materials, red based color materials, and other various deep colorbased color materials, and are in particular preferably black basedcolor materials. The color material to be used may be a pigment, a dyeor some other. Regarding the color material, a single species thereof,or a combination of two or more species thereof may be used. The dye isnot particularly limited, and may be any one of acid dyes, reactivedyes, direct dyes, dispersed dyes, and cationic dyes and other dyes. Thepigment is not particularly limited, either, and may be appropriatelyselected from known pigments.

Particularly, in the case of using a dye as the color material, the dyeturns into the state of being evenly dissolved or dispersed in the firstthermosetting resin layer. For this reason, the first thermosettingresin layer can easily be produced to have an even or substantially evencolor density. Thus, when a dye is used as the color material, the colordensity of the first thermosetting resin layer can be made even orsubstantially even, so that the semiconductor devices can be improved inmarking property or external appearance.

The black based color material to be used is not particularly limited,and may be selected from inorganic black based pigments and black baseddyes. The black based color material may be a color material mixturewherein a cyan based color material (bluish green based color material),a magenta based color material (reddish purple color material), and ayellow based color material are mixed with each other. In regards to theblack based color material, a single species thereof, or a combinationof two or more species thereof may be used. Of course, the black basedcolor material may be used together with a color material having a colorother than black.

Specific examples of the black based color material include carbonblacks (such as furnace black, channel black, acetylene black, thermalblack, and lamp black), graphite, copper oxide, manganese dioxide, azopigments (such as azomethine azo black), aniline black, perylene black,titanium black, cyanine black, activated carbon, ferrites (such asnonmagnetic ferrite, and magnetic ferrite), magnetite, chromium oxide,iron oxide, molybdenum disulfide, chromium complexes, complex oxidebased black colorants, and anthraquinone based organic black colorants.

Other examples of the black based color material usable in the presentembodiment include C.I. Solvent Blacks 3, 7, 22, 27, 29, 34, 43 and 70,C.I. Direct Blacks 17, 19, 22, 32, 38, 51 and 71, C.I. Acid Blacks 1, 2,24, 26, 31, 48, 52, 107, 109, 110, 119 and 154, C.I. Disperse Blacks 1,3, 10 and 24, and other black based dyes; and C.I. Pigment Blacks 1 and7, and other black based pigments.

As such a black based color material, the following are commerciallyavailable: color materials (trade names: “Oil Black BY”, “Oil Black BS”,“Oil Black HBB”, “Oil Black 803”, “Oil Black 860”, “Oil Black 5970”,“Oil Black 5906”, and “Oil Black 5905”) manufactured by Orient ChemicalIndustries Ltd.; and others.

Examples of color materials other than black based color materialsinclude can based color materials, magenta based color materials, andyellow based color materials. Examples of the cyan based color materialsinclude C.I. Solvent Blues 25, 36, 60, 70, 93 and 95, C.I. Acid Blues 6and 45, and other cyan based dyes; and C.I. Pigment Blues 1, 2, 3, 15,15:1, 15:2, 15:3, 15:4, 15:5, 15:6, 16, 17, 17:1, 18, 22, 25, 56, 60,63, 65 and 66, C.I. Vat Blues 4 and 60, C.I. Pigment Green 7, and othercyan based pigments.

Examples of the magenta based color materials include magenta based dyessuch as C.I. Solvents Reds 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63,81, 82, 83, 84, 100, 109, 111, 121 and 122; C.I. Disperse Red 9; C.I.Solvent Violets 8, 13, 14, 21 and 27; C.I. Disperse Violet 1; C.I. BasicReds 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35,36, 37, 38, 39 and 40; C.I. Basic Violets 1, 3, 7, 10, 14, 15, 21, 25,26, 27 and 28.

Other examples of the magenta based color materials include magentabased pigments such as C.I. Pigment Reds 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39,40, 41, 42, 48:1, 48:2, 48:3, 48:4, 49, 49:1, 50, 51, 52, 52:2, 53:1,54, 55, 56, 57:1, 58, 60, 60:1, 63, 63:1, 63:2, 64, 64:1, 67, 68, 81,83, 87, 88, 89, 90, 92, 101, 104, 105, 106, 108, 112, 114, 122, 123,139, 144, 146, 147, 149, 150, 151, 163, 166, 168, 170, 171, 172, 175,176, 177, 178, 179, 184, 185, 187, 190, 193, 202, 206, 207, 209, 219,222, 224, 238 and 245; C.I. Pigment Violets 3, 9, 19, 23, 31, 32, 33,36, 38, 43 and 50; and C.I. Vat Reds 1, 2, 10, 13, 15, 23, 29 and 35.

Examples of the yellow based color materials include yellow based dyessuch as C.I. Solvent Yellows 19, 44, 77, 79, 81, 82, 93, 98, 103, 104,112 and 162; and yellow based pigments such as C.I. Pigment Oranges 31and 43, and C.I. Pigment Yellows 1, 2, 3, 4, 5, 6, 10, 11, 12, 13, 14,15, 16, 17, 23, 24, 34, 35, 37, 42, 53, 55, 65, 73, 74, 75, 81, 83, 93,94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 113, 114, 116, 117, 120,128, 129, 133, 138, 139, 147, 150, 151, 153, 154, 155, 156, 167, 172,173, 180, 185 and 195; and C.I. Vat Yellows 1, 3 and 20.

Color materials of various kinds, such as the cyan based colormaterials, the magenta based color materials or the yellow based colormaterials, may be used alone or in combination of two or more thereof.When the color materials, such as the cyan based color materials, themagenta based color materials or the yellow based color materials, areused in combination of two or more thereof, the mixing ratio between thetwo or more (or the blend ratio of each of the two or more) is notparticularly limited, and may be appropriately selected in accordancewith the individual species of the color materials, a target color, andothers.

When the first thermosetting resin layer 1 is colored, the form ofcoloring is not particularly limited. The first thermosetting resinlayer 1 may be, for example, in the form of a mono-layered film to whicha coloring agent is added, or in the form of a laminated film having aresin layer at least made of a thermosetting resin and a coloring agentlayer laminated thereon. When the first thermosetting resin layer 1 is alaminated film having a resin layer and a coloring agent layer, thefirst thermosetting resin layer 1 is preferably in the lamination formof “resin layer/color material layer/resin layer”. In this case, the tworesin layers on both sides of the coloring agent layer may be resinlayers having the same composition, or resin layers having differentcompositions.

(Method for Forming the Supporting Structure)

A method for forming the supporting structure used in the presentembodiment includes the step of laminating the radiation curablepressure-sensitive adhesive layer 3 onto the support 4, and the step oflaminating the first thermosetting resin layer 1 onto the radiationcurable pressure-sensitive adhesive layer 3.

First, the support 4 is prepared. For example, a glass support as thesupport 4 may be a commercially available product, or may be a support 4of a predetermined shape that is obtained by subjecting a glass platehaving a predetermined thickness to cutting or some other treatment.When the support 4 is made of resin, examples of a method for forming afilm thereon include calendar film-forming method, a casting method inan organic solvent, an inflation extruding method in a closed system, aT-die extruding method, a co-extruding method, and a dry laminatingmethod. Hereinafter, the supporting-structure-forming method will bedescribed in regards to a case wherein the support 4 made of glass isused.

The radiation curable pressure-sensitive adhesive layer 3 may be formedby coating a solution of a radiation curable pressure-sensitive adhesivecomposition onto a release film, drying the workpiece underpredetermined conditions (and optionally crosslinking a crosslinkablecomponent therein by heat) to form a coating film, and then transferringthis coating film onto the support 4. The coating method is notespecially limited, and examples thereof include roll coating, screencoating, and gravure coating. The coating thickness is appropriately setso that the thickness of the radiation curable pressure-sensitiveadhesive layer 3 that can be eventually obtained by drying the coatinglayer falls within a range of 10 to 100 μm. The viscosity of thepressure-sensitive adhesive composition solution is not especiallylimited. However, it is preferably 100 to 5000 mPa·s, and morepreferably 200 to 3000 mPa·s at 25° C.

The method of drying the coating layer is not especially limited.However, it is preferably dried without using a dry wind when forming apressure-sensitive adhesive layer having a flat surface, for example.The drying time can be appropriately set according to the applicationamount of the pressure-sensitive adhesive composition solution; it isnormally within a range of 0.5 to 5 min, and preferably within a rangeof 2 to 4 min. The drying temperature is not especially limited; it isnormally 80 to 150° C., and preferably 80 to 130° C.

The radiation curable pressure-sensitive adhesive layer 3 may be formedby coating a pressure-sensitive adhesive composition directly onto thesupport 4 to form a coating film thereof, and then drying the coatingfilm under the above-described drying conditions.

The release film is not especially limited. However, an example thereofis a film in which a release coating layer such as a silicone layer isformed on the surface of the release film which is pasted onto theradiation curable pressure-sensitive adhesive layer 3 on the support.Examples of the support of the release film include paper such asglassine paper and a resin film made of polyethylene, polypropylene, orpolyester such as polyethylene terephthalate (PET).

Next, the radiation curable pressure-sensitive adhesive layer 3 on therelease film is transferred onto the support 4. The transferring isattained by pressure bonding. The bonding temperature is usually from 25to 100° C., preferably from 25 to 50° C. The bonding pressure is usuallyfrom 0.1 to 0.6 Pa, preferably from 0.2 to 0.5 Pa.

The method for forming the first thermosetting resin layer 1 may be, forexample, a method of coating, onto a release film 12 a, a solution of anadhesive composition that is a constituting material of the firstthermosetting resin layer 1 to form a coating film, and then drying thecoating film (see FIG. 1A). The release film 12 a may be the samerelease film as described above.

The method of applying the adhesive composition solution is notespecially limited. However, an example is a method of applying thesolution using a comma coating method, a fountain method, a gravuremethod, or the like. The application thickness is appropriately set sothat the thickness of the first thermosetting resin layer 1 that can beeventually obtained by drying the coating layer falls within a range of5 to 250 μm. The viscosity of the adhesive composition solution is notespecially limited. However, it is preferably 400 to 2500 mPa·s, andmore preferably 800 to 2000 mPa·s at 25° C.

The drying of the coating layer is performed by blowing a dry wind overthe coating layer. Examples of the method of blowing a dry wind includea method of blowing a dry wind so that the direction of blowing becomesparallel to the direction of transporting the release film and a methodof blowing a dry wind so that the direction of blowing becomesperpendicular to the surface of the coating layer. The flow of the drywind is not especially limited, and it is normally 5 to 20 m/min, andpreferably 5 to 15 m/min. With the flow of the dry wind being 5 m/min ormore, the drying of the coating layer is prevented from becominginsufficient. On the other hand, with the flow of the dry wind being 20m/min or less, the concentration of the organic solvent in the vicinityof the surface of the coating layer becomes uniform, and therefore,evaporation of the solvent can be made uniform. As a result, a firstthermosetting resin layer 1 having a uniform surface can be formed.

The drying time is appropriately set according to the applied thicknessof the adhesive composition solution; it is normally within a range of 1to 5 min, and preferably within a range of 2 to 4 min. When the dryingtime is less than 1 min, the curing reaction does not proceedsufficiently, and the amount of unreacted curing component and theamount of the remained solvent becomes large. Accordingly, problems ofoutgassing and voids may occur in the subsequent steps. On the otherhand, when it exceeds 5 min, the curing reaction proceeds too much. As aresult, fluidity, and tackiness to the semiconductor wafer maydeteriorate.

The drying temperature is not especially limited, and it is normally setwithin a range of 70 to 160° C. However, the drying temperature ispreferably increased stepwise with the passage of the drying time in thepresent embodiment. Specifically, it is set within a range of 70 to 100°C. at an initial stage of the drying (1 min or less from immediatelyafter the start of the drying), and it is set within a range of 100 to160° C. at a late stage of the drying (more than 1 min to 5 min or less)for example. Accordingly, pin holes on the surface of the coating layerthat form when the drying temperature is rapidly increased right afterthe start of the coating can be prevented.

Subsequently, the first thermosetting resin layer 1 is transferred ontothe radiation curable pressure-sensitive adhesive layer 3 (see FIG. 1B).The transferring can be attained by a known method such as laminating orpressing. The temperature for bonding the first thermosetting resinlayer onto the radiation curable pressure-sensitive adhesive layer ispreferably from room temperature to 150° C. In order to restrain theadvance of curing reaction in the first thermosetting resin layer 1, thetemperature is more preferably from room temperature to 100° C. Thebonding pressure is from 0.5 to 50 MPa, preferably from 0.5 to 10 MPa.

The first thermosetting resin layer 1 may be formed by coating anadhesive composition solution directly onto the radiation curablepressure-sensitive adhesive layer 3 to form a coating film thereof, andthen drying the coating film under the above-described dryingconditions.

The above-described release film 12 a may be peeled after the firstthermosetting resin layer 1 is bonded onto the radiation curablepressure-sensitive adhesive layer 3, or may be used, as it is, as aprotecting film for the supporting structure 10 and then peeled when thesemiconductor chips are to be arranged onto the first thermosettingresin layer 1. In this way, the supporting structure 10 of the presentembodiment can be produced.

[Semiconductor Chip Arranging Step]

In a semiconductor chip arranging step, the semiconductor chips 5 arearranged onto the first thermosetting resin layer 1 so that the firstthermosetting layer 1 and the second main surface 5 b opposite to thefirst main surfaces 5 a of the semiconductor chips 5 face each other(see FIG. 2A). For the arrangement of the semiconductor chips 5, a knownapparatus, such as a flip chip bonder or a die bonder, may be used.

The layout of the arrangement of the semiconductor chips 5, and thenumber of the chips 5 to be arranged may be appropriately set inaccordance with the shape and the size of the supporting structure 10,the number of the target semiconductor devices to be produced, andothers. The chips 5 may be arranged into the form of a matrix havingplural rows and plural columns.

[Second Thermosetting Resin Layer Laminating Step]

In a second thermosetting resin layer laminating step, a secondthermosetting resin layer 2 is laminated on the first thermosettingresin layer 1 to cover the semiconductor chips 5 (see FIG. 2B). Thissecond thermosetting resin layer 2 functions as a sealing resin forprotecting the semiconductor chips 5 and elements attached thereto fromthe external environment.

The method for laminating the second thermosetting resin layer 2 is notparticularly limited, and examples thereof include a method of extrudinga melted and kneaded product of a resin composition for forming thesecond thermosetting resin layer, placing the extruded product onto thefirst thermosetting resin layer 1, and then pressing the workpiece toattain the formation and the laminating of the second thermosettingresin layer at a time; a method of coating a resin composition for thesecond thermosetting resin layer onto the first thermosetting resinlayer 1, and then drying the workpiece; and a method of coating the sameresin composition onto a release treatment sheet, drying the resultantcoating film to form the sheet-like second thermosetting resin layer 2,and further transferring the second thermosetting resin layer 2 onto thefirst thermosetting resin layer 1.

In the present embodiment, the second thermosetting resin layer 2 ispreferably a sheet-like thermosetting resin layer. When the secondthermosetting resin layer 2 is made in a sheet-like state (thesheet-like second thermosetting resin layer may be referred to as the“sheet-like second resin layer” hereinafter), the semiconductor chips 5can be buried only by bonding the second thermosetting resin layer 2onto the first thermosetting resin 1 in order to cover the semiconductorchips 5. Thus, the production efficiency of the semiconductor devicescan be improved. In this case, the second thermosetting resin layer 2can be laminated onto the first thermosetting resin layer 1 by a knownmethod, such as hot pressing, or laminating using a laminator. Inregards to conditions for the hot pressing, the temperature is, forexample, from 40 to 120° C., preferably from 50 to 100° C., the pressureis, for example, from 50 to 2,500 kPa, preferably from 100 to 2,000 kPa,and the period is, for example, from 0.3 to 10 minutes, preferably from0.5 to 5 minutes. Considering improvements in the adhesiveness andfollowability of the second thermosetting resin layer 2 onto thesemiconductor chips 5, the pressing is performed preferably under areduced pressure (for example, a pressure of 10 to 2,000 Pa).

In this way, the second thermosetting resin layer 2 is laminated on thefirst thermosetting resin layer 1, and subsequently the two are cured.The curing of the second thermosetting resin layer and the firstthermosetting resin layer is attained by heating into the range oftemperatures of 120 to 190° C. under a pressure of 0.1 to 10 MPa for aheating period of 1 to 60 minutes.

The curing of the second thermosetting resin layer and the firstthermosetting resin layer may be performed before or after the radiationcurable pressure-sensitive adhesive layer and the first thermosettingresin layer 1 are peeled from each other. Before the peeling, the curingmay be advanced into some degree and then completed after the peeling.

(Second Thermosetting Resin Layer)

A resin composition for forming the second thermosetting resin layer isnot particularly limited as far as the composition can be used to sealthe semiconductor chips. A preferred example thereof is an epoxy resincomposition comprising the following components A to E:

component A: an epoxy resin,

component B: a phenolic resin,

component C: an elastomer,

component D: an inorganic filler, and

component E: a curing accelerator.

(Component A)

The epoxy resin (component A) is not particularly limited, and examplesthereof include triphenyl methane, cresol novolak, biphenyl, modifiedbisphenol A, bisphenol A, bisphenol F, modified bisphenol F,dicyclopentadiene, phenol novolak, phenoxy resin, and other varioustypes of epoxy resins. These epoxy resins may be used alone or incombination of two or more thereof.

The epoxy resin is preferably an epoxy resin which is in a solid form atroom temperature, and has an epoxy equivalent of 150 to 250 and asoftening point or melting point of 50 to 130° C. in order to certainlysecure a reactivity and a toughness after being cured. Particularlypreferred are triphenylmethane, cresol novolak, and biphenyl type epoxyresins, from the viewpoint of the reliability.

The epoxy resin is preferably modified bisphenol A type epoxy resinwhich has a flexible skeleton such as an acetal group or apolyoxyalkylene group, from the viewpoint of a low stress propertythereof. The epoxy resin is in particular preferably modified bisphenolA type epoxy resin which has an acetal group because the resin is in aliquid form and is good in its handling property.

The content by percentage of the epoxy resin (component A) is preferablyset into the range of 1 to 10% by weight of the epoxy resin composition.

(Component B)

The phenolic resin (component B) is not particularly limited as far asthe resin causes a curing reaction with the epoxy resin (component A).Examples thereof include phenol novolak resin, phenol aralkyl resin,biphenyl aralkyl resin, dicyclopentadiene type phenolic resin, cresolnovolak resin, and resol resin. These phenolic resins may be used aloneor in combination of two or more thereof.

The phenolic resin is preferably a resin having a hydroxyl equivalent of70 to 250 and a softening point of 50 to 110° C. from the viewpoint ofthe reactivity thereof with the epoxy resin (component A). The phenolicresin is in particular preferably phenol novolak resin because the resinis high in curing reactivity. Moreover, from the viewpoint of thereliability, the phenolic resin is a low-hygroscopicity phenolic resinsuch as phenol aralkyl resin or biphenyl aralkyl resin can be preferablyused.

In regards to the blend ratio between the epoxy resin (component A) andthe phenolic resin (component B), the amount of the hydroxyl groups inthe phenolic resin (component B) is preferably from 0.7 to 1.5equivalents, more preferably 0.9 to 1.2 equivalents per equivalent ofepoxy groups in the epoxy resin (component A), from the viewpoint of thecuring reactivity therebetween.

(Component C)

The elastomer (component C) used together with the epoxy resin(component A) and the phenolic resin (component B) is a component forgiving the epoxy resin composition a flexibility necessary for sealingthe semiconductor chips 5 when the second thermosetting resin layer ismade into a sheet-like state. The structure thereof is not particularlylimited as far as the elastomer produces such an effect. Examplesthereof include various acrylic copolymers such as polyacrylate,styrene/acrylate copolymers, butadiene rubber, styrene/butadiene rubber(SBR), ethylene/vinyl acetate copolymer (EVA), isoprene rubber,acrylonitrile rubber, and other rubbery polymers. The component C is inparticular preferably acrylic copolymer because the copolymer is easilydispersed into the epoxy resin (component A) and is further high inreactivity with the epoxy resin (component A) so that the copolymer canimprove the resultant second thermosetting resin layer in heatresistance and strength. These elastomers may be used alone or incombination of two or more thereof.

Acrylic copolymer may be synthesized, for example, by subjecting anacrylic monomer mixture where the ratio between the monomers is set to apredetermined value for radical polymerization in a usual way. Themethod for the radical polymerization may be a solution polymerization,wherein an organic solvent is used, or a suspension polymerization,wherein monomers as raw materials are polymerized while dispersed. Atthis time, a polymerization initiator may be used, and examples thereofinclude 2,2′-azobisisobutyronitrile,2,2′-azobis-(2,4-dimethylvaleronitrile),2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, and other azo or diazopolymerization initiators; and benzoyl peroxide, methyl ethyl ketoneperoxide, and other peroxide polymerization initiators. In thesuspension polymerization, it is desired to add a dispersing agent, suchas polyacrylamide or polyvinyl alcohol, to the system.

The content by percentage of the elastomer (component C) is from 15 to30% by weight of the whole of the epoxy resin composition. If thecontent by percentage of the elastomer (component C) is less than 15% byweight, the sheet-like second resin layer 2 does not easily gainflexibility or plasticity. Furthermore, it is difficult to seal with theresin while restraining warping of the second thermosetting resin layer.Conversely, if the content by percentage is more than 30% by weight, thesheet-like second resin layer 2 is raised in melt viscosity to belowered in performance of burying the semiconductor chips 5 therein.Additionally, the cured product of the sheet-like second resin layer 2tends to decline in strength and heat resistance.

The ratio by weight of the elastomer (component C) to the epoxy resin(component A) is preferably set into the range of 3 to 4.7. If thisratio by weight is less than 3, the fluidity of the sheet-like secondresin layer 2 is not easily controlled. If the ratio is more than 4.7,the sheet-like second resin layer 2 tends to be poor in tackiness ontothe semiconductor chips 5.

(Component D)

The inorganic filler (component D) is not particularly limited, and maybe various fillers known in the prior art. Examples thereof includequartz glass, talc, silica (such as fused silica or crystalline silica),alumina, aluminum nitride, silicon nitride, and some-other-materialpowders. These tillers may be used alone or in combination of two ormore thereof.

The inorganic filler is in particular preferably silica powder becausethe cured product of the epoxy resin composition is decreased in linearthermal expansion coefficient, which decreases internal stresses in thecured product so that after the sealing of the semiconductor chips 5,the second thermosetting resin layer 2 can be inhibited from warping.Out of silica powder species, fused silica powder is more preferred.Examples of the fused silica powder include spherical fused silicapowder, and crashed fused silica powder. From the viewpoint of fluidity,spherical fused silica powder is particularly preferred. The averageparticle diameter thereof is preferably from 0.1 to 30 μm, in particularpreferably from 0.3 to 15 μm.

The average particle diameter may be gained, for example, by measurementusing a laser diffraction scattering type particle size distributionmeasuring device on a sample extracted arbitrarily from a population ofthe particles.

The content by percentage of the inorganic filler (component D) ispreferably from 50 to 90% by weight, more preferably from 55 to 90% byweight, even more preferably from 60 to 90% by weight of the whole ofthe epoxy resin composition. If the content by percentage of theinorganic filler (component D) is less than 50% by weight, the curedproduct of the epoxy resin composition is increased in linear thermalexpansion coefficient so that the second thermosetting resin layer 2tends to be largely warped. On the other hand, if the content bypercentage is more than 90% by weight, the second thermosetting resinlayer 2 is deteriorated in flexibility or fluidity so that the secondthermosetting resin layer 2 tends to be reduced in tackiness to thesemiconductor chips 5.

(Component E)

The curing accelerator (component E) is not particularly limited as faras the component advances the curing of the epoxy resin and the phenolicresin. From the viewpoint of curing performance and storability,preferred examples of the component E include organic phosphoruscompounds such as triphenylphosphine and tetraphenylphosphoniumtetraphenylborate, and imidazole compounds. These curing acceleratorsmay be used alone or together with another curing accelerator.

The content of the curing accelerator (component F) is preferably from0.1 to 5 parts by weight for 100 parts by weight of the total of theepoxy resin (component A) and the phenolic resin (component B).

(Other Components)

Besides the components A to E, a flame retardant component may beincorporated into the epoxy resin composition. The flame retardantcomponent may be various metal hydroxides such as aluminum hydroxide,magnesium hydroxide, iron hydroxide, calcium hydroxide, tin hydroxide,or any complexed metal hydroxide. Preferred is aluminum hydroxide ormagnesium hydroxide, and particularly preferred is aluminum hydroxidefrom the viewpoint of costs and an advantage that the metal hydroxidecan exhibit flame retardancy in a relatively small addition amountthereof.

The average particle diameter of the metal hydroxide is preferably from1 to 10 μm, more preferably from 2 to 5 μm because the diameter permitsthe epoxy resin composition to keep an appropriate fluidity certainlywhen the composition is heated. If the average particle diameter of themetal hydroxide is less than 1 μm, the metal hydroxide cannot be evenlydispersed in the epoxy resin composition with ease, and further tendsnot to permit the epoxy resin composition to gain a sufficient fluiditywhen the composition is heated. If the average particle diameter is morethan 10 μm, the surface area of the metal hydroxide (component E) peraddition amount thereof is small so that the flame retardant effecttends to be reduced.

As the flame retardant component, a phosphazene compound may be usedbesides the metal hydroxides. The phosphazene compound may be obtainedas a commercially available product, examples of which include products(trade names: for example, SPR-100, SA-100, and SP-100) eachmanufactured by Otsuka Chemical Co., Ltd., and products (trade names:for example, FP-100, and FP-110) each manufactured by FushimiPharmaceutical Co., Ltd.

The phosphazene compound is preferably a phosphazene compoundrepresented by the following formula (1) or (2) because the compoundproduces a flame retardant effect even in a small amount:

wherein, in the formula (1), n is an integer of 3 to 25, R¹s and R²s,which may be the same or different, are each a monovalent organic grouphaving a functional group selected from the group consisting of alkoxy,phenoxy, amino, hydroxyl and allyl groups; or

wherein, in the formula (2), n and m are each independently an integerof 3 to 25; R³s and R⁵s, which may be the same or different, are each amonovalent organic group having a functional group selected from thegroup consisting of alkoxy, phenoxy, amino, hydroxyl and ally groups;and R⁴ is a bivalent organic group having a functional group selectedfrom the group consisting of alkoxy, phenoxy, amino, hydroxyl and allylgroups. The content by percentage of the phosphorus element in thephosphazene compounds is preferably 12% or more by weight.

It is preferred to use a cyclic phosphazene oligomer represented by thefollowing formula (3) from the viewpoint of the stability thereof andthe restrain of the generation of voids:

wherein, in the formula (3), n is an integer of 3 to 25, and R⁶s andR⁷s, which may be the same or different, are each hydrogen, or ahydroxyl, alkyl, alkoxy or glycidyl group.

The cyclic phosphazene oligomer represented by the formula (3) may beobtained as a commercially available product, examples of which includeproducts (trade names: for example, FP-100, and FP-110) eachmanufactured by Fushimi Pharmaceutical Co., Ltd.

The content by percentage of the phosphazene compound is preferably from10 to 30% by weight of the organic components contained in the epoxyresin composition, which comprise the epoxy resin (component A), thephenolic resin (component B), the elastomer (component D), the curingaccelerator (component E) and the phosphazene compound (anothercomponent). In other words, if the content by percentage of thephosphazene compound is less than 10% by weight of the organiccomponents, flame retardancy in the second thermosetting resin layer 2declines. Additionally, the second thermosetting resin layer 2 tends todecline in performance of following unevenness of adherends, so thatvoids are generated therebetween. If the content by percentage is morethan 30% by weight of the whole of the organic components, tackiness iseasily generated in the front surface of the second thermosetting resinlayer 2. As a result, especially when the second thermosetting resinlayer 2 is in particular, in a sheet-like state, the secondthermosetting resin layer 2 tends to decline in workability; thus, forexample, the position adjustment of the second thermosetting resin layerwith adherends becomes difficult.

When the metal hydroxide is used together with the phosphazene compound,the second thermosetting resin layer 2 can be obtained with excellentflame retardancy while the second thermosetting resin layer 2 certainlykeeps flexibility necessary for sealing with the sheet. The use of thetwo together makes it possible to achieve a sufficient flame retardancyobtained when only the metal hydroxide is used, and a sufficientflexibility obtained when only the phosphazene compound is used.

When the metal hydroxide is used together with the phosphazene compound,the content by percentage of the total of the two is from 70 to 90% byweight, preferably from 75 to 85% by weight of the whole of the epoxyresin composition. If the content by percentage of the total is lessthan 70% by weight, the second thermosetting resin layer 2 tends not togain a sufficient flame retardancy easily. If the content by percentageis more than 90% by weight, the second thermosetting resin layer 2 tendsto decline in adhesiveness to adherends, so that voids are generatedtherebetween.

If necessary, a pigment such as carbon black may be incorporated intothe epoxy resin composition, as may be other additives besides theabove-mentioned individual components.

(Method for Forming the Second Thermosetting Resin Layer)

Hereinafter, in regards to a case where the second thermosetting resinlayer is a sheet-like thermosetting resin layer, a procedure of a methodfor forming this layer will be described.

The above-described individual components are first mixed with eachother to prepare an epoxy resin composition. The method for the mixingis not particularly limited as far as the method is a method capable ofdispersing and mixing the individual components evenly. Thereafter, forexample, the individual components are dissolved or dispersed into anorganic solvent or some other to prepare a varnish. The thus-obtainedvarnish is coated into a sheet-like state. Alternatively, it isallowable to mix and knead the individual blend components directly bymeans of a kneader or some other to prepare a kneaded product, andextrude the thus obtained kneaded product into a sheet-like state.

In the formation procedure using the varnish, the components A to E andoptional other additives are appropriately mixed with each other in ausual way, and dissolved or dispersed evenly in an organic solventprepare the varnish. Next, the varnish is coated onto a support made ofpolyester or some other material, and then dried. In this way, thesecond thermosetting resin layer 2 can be yielded. If necessary, apeeling sheet, such as a polyester film, may be bonded onto the surfaceof the second thermosetting resin layer to protect the surface. Thepeeling sheet is peeled when the semiconductor chips are sealed.

The organic solvent is not particularly limited, and may beconventionally known organic solvents such as methyl ethyl ketone,acetone, cyclohexanone, dioxane, diethyl ketone, toluene, and ethylacetate. These may be used alone or in combination of two or morethereof. It is usually preferred to use the organic solvent to adjustthe solid concentration in the varnish into the range of 30 to 60% byweight.

After the removal of the organic solvent by the drying, the thickness ofthe sheet is not particularly limited. Usually, the thickness is setpreferably into the range of 5 to 100 μm, more preferably in that of 20to 70 μm from the viewpoint of the evenness of the thickness, and theremaining amount of the solvent.

In the meantime, in the process using the kneading, the components A toE and optional other additives are mixed with each other by a knownmeans such as a mixer, and then the mixture is melted and kneaded toprepare a kneaded product. The manner for the melting and kneading isnot particularly limited. An example thereof is a melting and kneadingmanner using a known kneader such as a mixing roll, a pressure kneaderor an extruder. Conditions for the kneading are not particularly limitedas far as the temperature therefor is equal to or higher than therespective softening points of the above-mentioned components. Thetemperature is, for example, from 30 to 150° C. Considering thethermosetting property of the epoxy resin, the temperature is preferablyfrom 40 to 140° C., more preferably from 60 to 120° C., and the periodis, for example, from 1 to 30 minutes and is preferably from 5 to 15minutes. Through this process, the kneaded product can be prepared.

The resultant kneaded product is shaped by extrusion, whereby the secondthermosetting resin layer 2 can be yielded. Specifically, after themelting and kneading, the kneaded product is extruded in the state ofbeing kept at the high temperature state without being cooled, wherebythe second thermosetting resin layer 2 can be formed. The method for theextrusion is not particularly limited, and examples thereof includeT-die extrusion, roll rolling, roll kneading, co-extrusion, and calendarforming methods. The extruding temperature is not particularly limitedas far as the temperature is equal to or higher than the respectivesoftening points of the above-mentioned individual components.Considering the thermosetting property and the formability of the epoxyresin, the temperature is, for example, from 40 to 150° C., preferablyfrom 50 to 140° C., even more preferably from 70 to 120° C. Through thisprocess, the second thermosetting resin layer 2 can be formed.

The thus yielded second thermosetting resin layers may be laminated ontoeach other into a desired thickness if necessary. In other words, thesheet-like epoxy resin composition may be used in the form of amonolayered structure, and may also be used in the form of a laminatehaving a multilayered structure composed of two or more layers.

[Step of Exposing Electroconductive Member]

In the present embodiment, after the laminating of the secondthermosetting resin layer 2 and before the peeling of the radiationcurable pressure-sensitive adhesive layer 3, the electroconductivemembers 6 are exposed outward from the surface of the secondthermosetting resin layer 2 (FIG. 2C).

The method for exposing the electroconductive members 6 is notparticularly limited. An example thereof includes a method of applying,to the surface of the second thermosetting resin layer 2, polishing,laser radiation, cutting, dry etching or some other treatment. Themethod is preferably the polishing of the surface of the secondthermosetting resin layer 2 because the surface flatness of the secondthermosetting resin layer 2 is certainly maintained and theelectroconductive members 6 can be made exposed in parallel. In thiscase, the surface of the second thermosetting resin layer 2 surface andthe exposed region of the electroconductive members 6 are insubstantially the same plane (that is, these two form a single plane).

[Radiation Curable Pressure-Sensitive Adhesive Layer Peeling Step]

In a radiation curable pressure-sensitive adhesive layer peeling step,the radiation curable pressure-sensitive adhesive layer 3 is cured byirradiation from the support 4 side, thereby peeling the radiationcurable pressure-sensitive adhesive layer 3 and the first thermosettingresin layer 1 from each other (see FIG. 2D). The radiation curablepressure-sensitive adhesive layer 3 is irradiated to increase thecrosslinkage degree of the radiation curable pressure-sensitive adhesivelayer 3 to decrease the adhesive strength thereof. This manner makes itpossible to attain easily the peeling of the radiation curablepressure-sensitive adhesive layer 3 and the thermosetting resin layer 1from each other at the interface 7 therebetween (see FIG. 2C).

Conditions for the irradiation are not particularly limited as far asthe conditions permit the radiation curable pressure-sensitive adhesivelayer 3 to be cured. In the case of radiating, for example, ultravioletrays, the cumulative radiant exposure may be from about 10 to 1,000mJ/cm².

When, after the peeling, the second thermosetting resin layer 2 and thefirst thermosetting resin layer 1 are not completely cured, the secondthermosetting resin layer 2 and the first thermosetting resin layer 1may be cured if necessary.

Of course, the production method of the present embodiment may furtherinclude, after the peeling of the radiation curable pressure-sensitiveadhesive layer 3, exposing the electroconductive members 6 outward fromthe surface of the second thermosetting resin layer 2. In this way, theelectroconductive members 6 are made exposed outward from the surface ofthe second thermosetting resin layer 2, to be subjected to a rewiringstep. In order to expose the electroconductive members 6, the samemethods as described above may be used.

In the present step, in the state that respective tips of theelectroconductive members 6 are exposed to the surface of the secondthermosetting resin layer 2, the respective surfaces of theelectroconductive members 6 may be cleaned by plasma treatment or someother treatment before the rewiring step.

[Rewiring Step]

The present embodiment preferably includes the rewiring step. In thisstep, after the peeling of the radiation curable pressure-sensitiveadhesive layer 3, rewires 8 to be connected to the exposedelectroconductive members 6 are formed on the second thermosetting resinlayer 2 (see FIG. 2E).

The method for forming, the rewires may be, for example, a known methodof using a known way to form a metal seed layer onto the exposedelectroconductive members 6 and the second thermosetting resin layer 2,such as vacuum film deposition, and then performing a semi-additivemethod or some other known method to form the rewires 8.

Thereafter, an insulating layer made of polyimide, PBO or some othermaterial may be formed on the rewires 8 and the second thermosettingresin layer 2.

[Bump Forming Step]

Next, bumping processing may be performed wherein bumps 9 are formed onthe formed rewires 8 (see FIG. 2F). The bumping processing may beperformed in a known manner, such as a manner using solder balls orsolder plating. The material of the bumps is preferably the samematerial as used for the electroconductive members, which has beendescribed in the semiconductor chip preparing step.

[Dicing Step]

Finally, the laminate is diced which is composed of the firstthermosetting resin layer 1, the semiconductor chips 5, the secondthermosetting resin layer 2 and other optional elements such as therewires 8 (see FIG. 2G). This step can form semiconductor devices 11wherein the wires are drawn outward from its chip region. The dicing isperformed usually in the state that the laminate is fixed onto a dicingsheet known in the prior art. The position adjustment of sites to bediced in the laminate may be attained by image recognition usinginfrared rays (IR).

In the present step, a cutting manner called full cut may be used whenthe dicing sheet is cut. A dicing device used in the present step is notparticularly limited, and may be a device known in the prior art.

When the laminate is expanded after the dicing step, the expanding maybe performed using an expanding device known in the prior art. Theexpanding device has a donut-form outer ring capable of pushing thelaminated film downward through a ring for the dicing, and an inner ringthat is smaller in diameter than the outer ring and supports thelaminated film. This expanding step makes it possible to prevent anyadjacent two of the semiconductor devices 11 from being damaged bycontacting each other.

(Semiconductor Devices)

As has been illustrated in FIG. 2G, each of the semiconductor devices 11has the semiconductor chip 5 buried in the second thermosetting resinlayer 2, the first thermosetting resin layer 1 provided adjacently tothe second thermosetting resin layer 2 to cover the second main surface5 b of the semiconductor chip 5, one or more of the rewires 8 that areformed on the second thermosetting resin layer 2 and connected to someof the electroconductive members 6, and solder bumps 9 located on I/Opads of the one or more rewires 8.

EXAMPLES

Hereinafter, preferred working examples of this invention will bedemonstrated in detail. However, specific descriptions of materials,blend amounts and other factors in these examples do not limit the scopeof the invention to these factors unless there is any limiteddescription. The word “part(s)” denotes part(s) by weight.

(Formation of Radiation Curable Pressure-Sensitive Adhesive Layer)

Into a reactor equipped with a condenser tube, a nitrogen introducingtube, a thermostat, and a stirrer were put 86.4 parts of 2-ethylhexylacrylate (hereinafter also referred to as “2EHA”), 13.6 parts of2-hydroxyethyl acrylate (hereinafter also referred to as “HEA”), 0.2part of benzoyl peroxide, and 65 parts of toluene. Under a nitrogen gasflow, these components were subjected to polymerization treatment at 61°C. for 6 hours to yield an acrylic polymer A.

To the acrylic polymer A were added 14.6 parts of 2-methacryloyloxyethylisocyanate (hereinafter also referred to as “MOI”), and under an air gasflow, these components were subjected to addition reaction treatment at50° C. for 48 hours to yield an acrylic polymer A′.

Next, to 100 parts of the acrylic polymer A′ were added 8 parts of apolyisocyanate compound (trade name: “COLONATE L”, manufactured byNippon Polyurethane Industry Co., Ltd.), and 5 parts of aphotopolymerization initiator (trade name: “IRGACURE 651”, manufacturedby Ciba Specialty Chemicals Ltd.) to yield a pressure-sensitive adhesivecomposition solution A.

In each of the working examples and the comparative examples, theresultant pressure-sensitive adhesive composition solution A was coatedonto a polyethylene terephthalate film (PET film) subjected to releasetreatment and having a thickness of 50 μm, and then dried to form aradiation curable pressure-sensitive adhesive layer. The respectivethicknesses of the produced radiation curable pressure-sensitiveadhesive layers are shown in Table 1.

(Formation of First Thermosetting Resin Layer a)

The following were dissolved into methyl ethyl ketone: 5 parts of abisphenol A type epoxy resin having an epoxy equivalent of 185 g/eq.(trade name: YL-980, manufactured by Yuka Shell Epoxy Co., Ltd.); 15parts of a cresol novolak type epoxy resin having an epoxy equivalent of198 g/eq. (trade name: KI-3000-4, manufactured by Tohto Kasei Co.,Ltd.); 22.3 parts of an aralkyl type phenolic resin having a phenolequivalent of 175 g/eq. (trade name: MEHC-7851H, manufactured by MeiwaPlastic Industries, Ltd.); 227.5 parts of butylacrylate/acrylonitrile/ethyl acrylate copolymer (trade name: SG-70L,manufactured by Nagase ChemteX Corp.); and 1 part of triphenylphosphine(manufactured by Shikoku Chemicals Corp.) as a curing catalyst. Theretowere added 83 parts of an inorganic filler (trade name: SE2050MC,manufactured by Admatechs Co., Ltd.; average particle diameter: 0.5 μm)to prepare an adhesive composition solution having a solid concentrationof 32% by weight.

This adhesive composition solution was coated onto arelease-treatment-subjected film as a peeling liner (separator). Thefilm was a polyethylene terephthalate film having a thickness of 50 μmand subjected to silicone release treatment. The workpiece was thendried at 130° C. for 2 minutes to form a first thermosetting resinlayer, having a thickness as shown in Table 1.

(Formation of First Thermosetting Resin Layer b)

The following were dissolved into methyl ethyl ketone: 15 parts of abisphenol A type epoxy resin having an epoxy equivalent of 185 g/eq.(trade name: YL-980, manufactured by Yuka Shell Epoxy Co., Ltd.); 5parts of a cresol novolak type epoxy resin having an epoxy equivalent of198 g/eq. (trade name: KI-3000-4, manufactured by Tohto Kasei Co.,Ltd.); 23.1 parts of an aralkyl type phenolic resin having a phenolequivalent of 175 g/eq. (trade name: MEHC-7851H, manufactured by MeiwaPlastic Industries, Ltd.); 7.65 parts of butylacrylate/acrylonitrile/ethyl acrylate copolymer (trade name: SG-70L,manufactured by Nagase ChemteX Corp.); and 0.25 part oftriphenylphosphine (manufactured by Shikoku Chemicals Corp.) as a curingcatalyst. Thereto were added 34 parts of an inorganic filler (tradename: SE2050MC, manufactured by Admatechs Co., Ltd.; average particlediameter: 0.5 μm) to prepare an adhesive composition solution having asolid concentration of 32% by weight.

This adhesive composition solution was coated onto arelease-treatment-subjected film as a peeling liner (separator). Thefilm was a polyethylene terephthalate film having a thickness of 50 μmand subjected to silicone release treatment. The workpiece was thendried at 130° C. for 2 minutes to form a first thermosetting resin layerb having a thickness shown in Table 1.

(Formation of First Thermosetting Resin Layer c)

The following were dissolved into methyl ethyl ketone: 5 parts of abisphenol A type epoxy resin having an epoxy equivalent of 185 g/eq.(trade name: YL-980, manufactured by Yuka Shell Epoxy Co., Ltd.); 1.5parts of a cresol novolak type epoxy resin having an epoxy equivalent of198 g/eq. (trade name: KI-3000-4, manufactured by Tohto Kasei Co.,Ltd.); 22.3 parts of an aralkyl type phenolic resin having a phenolequivalent of 175 g/eq. (trade name: MEHC-7851H, manufactured by MeiwaPlastic Industries, Ltd.); 124.4 parts of butylacrylate/acrylonitrile/ethyl acrylate copolymer (trade name: SG-70L,manufactured by Nagase ChemteX Corp.); and 1 part of triphenylphosphine(manufactured by Shikoku Chemicals Corp.) as a curing catalyst. Theretowere added 124.4 parts of an inorganic filler (trade name: SE2050MC,manufactured by Admatechs Co., Ltd.; average particle diameter: 0.5 μm)to prepare an adhesive composition solution having a solid concentrationof 34% by weight.

This adhesive composition solution was coated onto arelease-treatment-subjected film as a peeling liner (separator). Thefilm was a polyethylene terephthalate film having a thickness of 50 μmand subjected to silicone release treatment. The workpiece was thendried at 130° C. for 2 minutes to form a first thermosetting resin layerc having a thickness as shown in Table 1.

(Formation of First Thermosetting Resin Layer d)

The following were dissolved into methyl ethyl ketone: 31.6 parts of anaphthalene type epoxy resin having an epoxy equivalent of 142 g/eq.(trade name: HP4032D, manufactured by DIC Corp.); 7.9 parts of atrishydroxyphenylmethane type epoxy resin having an epoxy equivalent of169 g/eq. (trade name: EPPN501HY, manufactured by Dainippon Ink &Chemicals. Inc.); 11.8 parts of an aralkyl type phenolic resin having aphenol equivalent of 175 g/eq. (trade name: MEHC-7851S, manufactured byMeiwa Plastic Industries, Ltd.); 35.5 parts of on aralkyl type phenolicresin having a phenol equivalent of 175 g/eq. (trade name: MEHC-7851H,manufactured by Meiwa Plastic Industries, Ltd.); 12 parts of butylacrylate/acrylonitrile/glycidyl methacrylate copolymer (trade name:SG-28GM, manufactured by Nagase ChemteX Corp.); and 1 part oftriphenylphosphine (manufactured by Shikoku Chemicals Corp.) as a curingcatalyst. Thereto were added 100 parts of an inorganic filler (tradename: SE2050MC, manufactured by Admatechs Co., Ltd.; average particlediameter: 0.5 μm) to prepare an adhesive composition solution having asolid concentration of 35% by weight.

This adhesive composition solution was coated onto arelease-treatment-subjected film as a peeling liner (separator). Thefilm was a polyethylene terephthalate having a thickness of 50 μm andsubjected to silicone release treatment. The workpiece was then dried at130° C. for 2 minutes to form a first thermosetting resin layer d havinga thickness shown in Table 1.

(Formation of First Thermosetting Resin Layer e)

The following were dissolved into methyl ethyl ketone: 5 parts of abisphenol A type epoxy resin having an epoxy equivalent of 185 g/eq.(trade name: YL-980, manufactured by Yuka Shell Epoxy Co., Ltd.); 15parts of a cresol novolak type epoxy resin having an epoxy equivalent of198 g/eq. (trade name: KI-3000-4, manufactured by Tohto Kasei Co.,Ltd.); 22.3 parts of an aralkyl type phenolic resin having a phenolequivalent of 175 g/eq. (trade name: MEHC-7851H, manufactured by MeiwaPlastic industries, Ltd.); 342 parts of butylacrylate/acrylonitrile/ethyl acrylate copolymer (trade name: SG-70L,manufactured by Nagase ChemteX Corp.); and 1 part of triphenylphosphine(manufactured by Shikoku Chemicals Corp.) as a curing catalyst. Theretowere added 149.5 parts of an inorganic filler (trade name: SE2050MC,manufactured by Admatechs Co., Ltd.; average particle diameter: 0.5 μm)to prepare an adhesive composition solution having a solid concentrationof 32% by weight.

This adhesive composition solution was coated onto arelease-treatment-subjected film as a peeling liner (separator). Thefilm was a polyethylene terephthalate film having a thickness of 50 μmand subjected to silicone release treatment. The workpiece was thendried at 130° C. for 2 minutes to form a first thermosetting resin layere having a thickness shown in Table 1.

(Formation of Supporting Structure)

A glass plate of 725 μm thickness was prepared as a support, and thenthe radiation curable pressure-sensitive adhesive layer formed asdescribed above was transferred onto the support by a laminator.Conditions for the laminating were as follows:

<Laminating Conditions>

Laminator: roll laminator

Laminating speed: 1 m/min

Laminating temperature: 45° C.

Next, the radiation curable pressure-sensitive adhesive layer and eachof the first thermosetting resin layers were bonded to each other by alaminator to yield a supporting structure. Conditions for the laminatingwere as follows:

<Laminating Conditions>

Laminator: roll laminator

Laminating speed: 3 m/min

Laminating temperature: 75° C.

(Arrangement of Semiconductor Chips)

The separator was peeled off from the first thermosetting resin layer ofthe supporting structure, and then a flip chip bonder was used toarrange semiconductor chips onto the first thermosetting resin layerunder conditions described below. At this time, the semiconductor chipswere arranged so that the respective back surfaces of the chips (thesurface opposite to the bump-formed surface) and the first thermosettingresin layer face to each other.

<Semiconductor Chips>

Semiconductor chip size: 7.3 mm square

Bump material: Cu (thickness: 30 μm), and Sn—Ag (thickness: 15 μm)

The number of the bumps: 544

Bump pitch: 50 μm

The number of the chips: 16 (4×4)

<Bonding Conditions>

Device: bonder manufactured by Panasonic Corp.

Bonding conditions: 150° C., 49 N, 10 sec.

(Formation of Kneaded Product of Second Thermosetting Resin Layer)

The following components A to E were melted and kneaded by a rollkneader at 80° C. for 10 minutes to yield a kneaded product:

Component A (epoxy resin): bisphenol F type epoxy resin (trade name:YSLV-80XY, manufactured by Tohto Kasei Co., Ltd.; epoxy equivalent: 200g/eq.; softening point: 80° C.) 5.7 parts

Component B (phenolic resin): phenolic resin having a biphenylaralkylskeleton (trade name: MEH7851SS, manufactured by Meiwa PlasticIndustries, Ltd.; hydroxyl equivalent: 203 g/eq.; softening point: 67°C.) 6.0 parts

Component C (elastomer): acrylic thermoplastic resin (trade name:LA-2140, manufactured by Kuraray Co., Ltd.) 3.6 parts

Component D (inorganic filler): spherical fused silica powder (tradename: FB-9454, manufactured by Denki Kagaku Kogyo K.K.; average particlediameter: 20 μm) 88 parts

Component E (curing accelerator): imidazole catalyst as a curingcatalyst (trade name: 2PHZ-PW, manufactured by Shikoku Chemicals Corp.)0.14 part

Examples 1 to 3 and Comparative Examples 1 and 2

In each of Examples 1 to 3 and Comparative Examples 1 and 2, theabove-mentioned kneaded product was extruded. The extruded product waslaminated onto one of the above-mentioned first thermosetting resinlayers by a reduced-pressure pressing so as to cover the semiconductorchips according to combinations of elements shown in Table 1. In thisway, a second thermosetting resin layer of 1 mm thickness was formed.Through the above-mentioned steps, a laminate according to each ofExamples 1 to 3 and Comparative Examples 1 and 2 was produced, which hadthe radiation curable pressure-sensitive adhesive layer, the firstthermosetting resin layer, the semiconductor chips and the secondthermosetting resin layer.

<Reduced-Pressure Pressing Conditions>

Device: press manufactured by Mikado Technos Co., Ltd.

Pressing conditions: pressing at 1.7 kN and 80° C. under a reducedpressure of 99.3 Pa for 1 minute, and then pressing at 8.5 kN and 80° C.under the same pressure for 2 minutes.

(Measurement of Respective Lowest Melt Viscosities of FirstThermosetting Resin Layers)

Before each of the first thermosetting resin layers was bonded to theradiation curable pressure-sensitive adhesive layer, the lowest meltviscosity of the first thermosetting resin layer was measured (beforethermally cured). The lowest melt viscosity was a value obtained bymeasuring the first thermosetting resin layer by a parallel plate methodusing a rheometer (trade name: RS-1, manufactured by HAAKE GmbH). Morespecifically, the melt viscosity was measured in the range oftemperatures of 50 to 200° C. under the following conditions: a gap of100 μm, a rotary cone diameter of 20 mm, and a rotating speed of 10 s⁻¹;and the lowest value out of the melt viscosities obtained at this timewas defined as the lowest melt viscosity. The results are shown in Table1.

(Check as to Whether or Not Semiconductor Chips were Shifted Out ofPosition at the Time of Laminating of Second Thermosetting Resin Layer)

When the second thermosetting resin layer was laminated onto the firstthermosetting resin layer in each of Examples 1 to 3 and ComparativeExamples 1 and 2, a length-measuring microscope (manufactured by KeyenceCorp.; magnification: ×500) was used to check whether or not therespective positions of the semiconductor chips on the firstthermosetting resin layer were changed. When the maximum value out ofthe respective position-change-quantities of the semiconductor chips was50 μm or less, the present sample was judged to be good. When themaximum value was more than 50 μm, the sample was judged to be bad. Asthe position-change-quantity of each of the semiconductor chips, thefollowing was used: the quantity of a change in the position of the apexof the semiconductor chip when viewed in plan before and afterobservation. The results are shown in Table 1.

(Measurement of Peeling Force Between Radiation CurablePressure-Sensitive Adhesive Layer and First Thermosetting Resin Layers)

In regards to the laminate according to each of Examples 1 to 3 andComparative Examples 1 and 2, a measurement was made regarding thepeeling force between the radiation curable pressure-sensitive adhesivelayer and the first thermosetting resin layer. Specifically, ultravioletrays were first radiated to the laminate from the support side thereofto cure the radiation curable pressure-sensitive adhesive layer. For theultraviolet ray radiation, an ultraviolet radiating device (trade name:MM810, manufactured by Nitto Seiki Co., Ltd.) was used. The ultravioletradiant exposure was set to 400 mJ/cm². Thereafter, between theradiation curable pressure-sensitive adhesive layer and the firstthermosetting resin layer, the peeling force (N/20 mm) was measured.More specifically, a device (trade name: “AUTOGRAPH AGS-H”) manufacturedby Shimadzu Corp. was used as a tensile tester to make a T-shape peelingtest (according to JIS K 6854-3) under the following conditions: atemperature of 23±2° C., a peeling angle of 180°, a peeling rate of 300mm/min, and a distance of 100 mm between its chucks. When the laminategave a peeling force of 20 N/20 mm or less, the laminate was judged tobe good. When the laminate gave a peeling force more than 20 N/20 mm,the laminate was judged to be bad. The results are shown in Table 1.

TABLE 1 Comparative Comparative Example 1 Example 2 Example 3 Example 1Example 2 Support Material PET PET PET PET PET Thickness (μm) 50 50 5050 50 Radiation curable Pressure-sensitive A A A A A pressure-sensitiveadhesive composition adhesive layer solution species Thickness (μm) 3030 30 30 30 First First thermosetting a b c d e thermosetting resinlayer species resin layer Thickness (μm) 70 70 70 70 70 Lowest meltviscosity 4.2 × 10² 5.6 × 10³ 7.0 × 10³ 1.0 × 10² 5.1 × 10⁴ (Pa · s)Evaluation as to whether or not Good Good Good Bad Bad semiconductorchips were shifted out of position Peeling force between radiationcurable Good Good Good Bad Good pressure-sensitive adhesive layer andfirst thermosetting resin layer after radiation of ultraviolet rays

As is evident from Table 1, in each of the laminates according toExamples 1 to 3, the lowest melt viscosity of the first thermosettingresin layer was in the range of 5×10² Pa·s or more and 1×10⁴ Pa·s orless; thus, when the second thermosetting resin layer was laminated, thesemiconductor chips were not shifted out of position. Moreover, theradiation curable pressure-sensitive adhesive layer and the firstthermosetting resin layer were able to be satisfactorily peeled fromeach other. On the other hand, in the laminate of Comparative Example 1,the semiconductor chips were shifted out of position, and further theradiation curable pressure-sensitive adhesive layer and the firstthermosetting resin layer were unable to be satisfactorily peeled fromeach other. It can be considered that this is because the firstthermosetting resin layer was increased in fluidity since the lowestmelt viscosity of the first thermosetting resin layer was less than5×10² Pa·s. In the laminate of Comparative Example 2, between theradiation curable pressure-sensitive adhesive layer and the firstthermosetting resin layer, the peeling force was good. However, thesemiconductor chips were shifted out of positions. It can be consideredthat this is because the lowest melt viscosity of the firstthermosetting resin layer was more than 1×10⁴ Pa·s, whereby the firstthermosetting resin layer was largely lowered in fluidity, so that theadhesive power to the chips was also declined.

What is claimed is:
 1. A method for producing a semiconductor deviceincluding a semiconductor chip, comprising: preparing semiconductorchips, each having a first main surface on which an electroconductivemember is formed; preparing a supporting structure in which over asupport configured to transmit radiation, a radiation curablepressure-sensitive adhesive layer and a first thermosetting resin layerare laminated in this order; arranging the semiconductor chips on thefirst thermosetting resin layer to face the first thermosetting resinlayer to a second main surface of each of the semiconductor chips thatis opposite to the first main surface thereof; laminating a secondthermosetting resin layer over the first thermosetting resin layer tocover the semiconductor chips; exposing an electroconductive memberoutward from a surface of the second thermosetting resin layer after thelaminating of the second thermosetting resin layer and before a peelingof the radiation curable pressure-sensitive adhesive layer; and curingthe radiation curable pressure-sensitive adhesive layer by irradiatingfrom a support side to peel the radiation curable pressure-sensitiveadhesive layer and the first thermosetting resin layer from each other.2. The method for producing a semiconductor device according to claim 1,wherein the first thermosetting resin layer has a lowest melt viscosityof 5×10² Pa·s or more and 1×10⁴ Pa·s or less at a temperature of 50 to200° C.
 3. The method for producing a semiconductor device according toclaim 1, wherein the second thermosetting resin layer is a sheet-likethermosetting resin layer.
 4. The method for producing a semiconductordevice according to claim 3, wherein the second thermosetting resinlayer comprises an epoxy resin, a phenolic resin, a filler, and anelastomer.
 5. The method for producing a semiconductor device accordingto claim 1, further comprising, after the peeling of the radiationcurable pressure-sensitive adhesive layer, exposing theelectroconductive member outward from the surface of the secondthermosetting resin layer.
 6. The method for producing a semiconductordevice according to claim 1, further comprising forming a rewireconnected to the exposed electroconductive member on the secondthermosetting resin layer.
 7. The method for producing a semiconductordevice according to claim 5, further comprising forming a rewireconnected to the exposed electroconductive member on the secondthermosetting resin layer.